Device for impregnating a web laterally guided in the width direction

ABSTRACT

The device for impregnating a web laterally guided in the width direction with a treatment liquid comprises a tank for the treatment liquid through which the web is taken on an impregnation section and a pair of squeeze rollers arranged above the tank between which the web can be taken from below immediately after leaving the tank. The tank takes the form of an upright flat channel, the flat sides of which are tightly opposed, through which the web can be taken upwards, which can be kept full up to an optional level and the lower end of which is limited by a resilient sealing arrangement bearing on the web from both sides.

BACKGROUND OF THE INVENTION

The invention relates to a device for impregnating a web, in particularfor impregnating a web laterally guided in the width direction with atreatment of fluid.

An application device with a flat, upright channel which can be filledwith treatment liquid, with a sealing arrangement of the type describedinitially, is actually known from DE-OS 14 60 265. However, in the knownembodiment, the web is guided through the flat channel from the top tothe bottom, and the squeeze rollers are arranged below the channel. Theyform a gore in which the treatment fluid which is squeezed off collects,and from which it is passed away laterally and brought back to acollecting tank, from which the supply tank can be refilled. Thisapplication device meets the general goal in textile technology ofconstantly reducing the amounts of treatment liquid in the apparatuses.

However, the arrangement of the pair of squeeze rollers below the supplytank, which is accompanied by filling of the gore with treatment liquidand the necessity of lateral sealing of the gore, is also notadvantageous when viewed from the aspect of uniformly squeezing off aselectable application amount, since a certain minimum pressure isrequired to seal the squeeze nip towards the bottom, which is equivalentto a maximum application amount.

Devices with pairs of squeeze rollers located above the supply tank aregenerally known in the form of a foulard, e.g. from DE 1 078 527 and DE1 054 048. Here, the web is passed from above into a trough which isopen towards the top and contains the treatment liquid. The web isdeflected upward over a deflection roller located near the bottom of thetrough. After exiting from the treatment liquid in the trough, the webis squeezed by means of the pair of squeeze rollers arranged above thetrough. The liquid which is squeezed off runs back into the trough via aguide surface.

Because of the presence of the deflection roller, the volume of thetrough is rather large, for design reasons. It is also known to housedisplacement elements in the trough, but there is still a significantvolume of liquid which must be stored or disposed of after the end oftreatment or if the treatment liquid is changed. Careful cleaning isdifficult due to the presence of the displacement elements.

Accordingly, an object of the invention is the further development of atreatment device of the type stated, in such a way that thedisadvantages of gore formation are avoided.

SUMMARY OF THE INVENTION

These and other objects are accomplished by providing a device forimpregnating a web laterally guided in the width direction with atreatment liquid. The device includes a tank for the treatment liquidthrough which the web is taken on an upright impregnation section, andwhich is formed by an upright flat channel, the flat sides of which aretightly opposed, which can be kept full up to an optional level. Thelower end of the channel is limited by a resilient sealing arrangementbearing on the web from both sides. A pair of squeeze rollers areincluded, between which the web can be taken. The pair of squeezerollers is arranged above the tank, and the web can be taken through thetank from bottom to top, and through the pair of squeeze rollers frombelow immediately after leaving the tank.

While the flat trough of a known foulard can hold the amount of liquidwithout sealing problems because of its trough shape, for this purposeit requires an interior which can hold the incoming section, theoutgoing section of the web and the deflection roller.

This trough is replaced in the present invention by the upright, flatchannel through which the web passes only once, from bottom to top, andwhich is limited, i.e. sealed with regard to liquids, at the bottom endby the sealing arrangement. The seal relative to the moving web replacesthe closed design of the trough, where the latter, however, requires theweb sections to be passed through twice.

The channel is supposed to be "flat." This means that the clear distancebetween the level flat sides of the channel which stand opposite andparallel to one another is just large enough for a web to be looselypassed through it guided in the width direction. For the impregnationeffect, it does not matter whether the web comes closer to one flatsurface or the other as it passes through the channel. The specificdistance dimension to be chosen in an individual case depends on thematerial. A material such as a cotton fabric requires only a slightdistance, as compared with a fluffy material or one with a nap.

The arrangement of the flat sides of the flat channel at the smallestpossible distance from the web has the effect, on the one hand, that thevolume of treatment liquid in the channel can be kept low, and, in thecase of a web with a width of 1800 mm, amounts to only about 11 liters.Such a small amount is quickly "used up" by the web passing through, sothat there are no problems with any depletion of the liquid.

On the other hand, however, the flatness of the channel also has aneffect on the physical efficacy of impregnation. Because the flat sidesof the channel are so close to the web, a flow interaction occurs, inthat strong turbulent flow layers occur on both sides of the web, thepressure pulsations of which promote de-aeration of the web andtherefore penetration of the treatment liquid into the web. The degreeof efficacy of impregnation, over a comparable impregnation distance,clearly increases as compared with conditions in a conventional foulardtank.

Because of the arrangement of the pair of squeeze rollers above thechannel, the problems of the filled gore and the limited applicationamount are eliminated.

The sealing arrangement at the bottom end of the channel can be madesuch that the flat channel is delimited, at its bottom end, at least onone side of the web, in a zone reaching crosswise across the web, by aflexible wall which can be inflated against the web by a fluid pressuremedium, resting tightly against it and forming a seal by pressingagainst a counter-surface on the other side of the web. Furthermore,inflatable, flexible walls may be provided on both sides of the web, andthe flexible walls may be formed by inflatable hoses which lie oppositeone another. However, this is actually known, for example from DE-OS 1460 268 and DE-OS 14 60 265.

The flat channel consists of rigid material. The flat sides of the flatchannel consist of two rectangular plates which are arranged oppositeand parallel to one another at a distance, which are tightly connectedwith one another on the upright edges by means of edge ridges made of arectangular profile, arranged between them. Materials for the channelare suitable plastics or corrosion-resistant steel. In the preferredexemplary embodiment, the clear distance between the flat sides of thechannel is approximately 6 to 15 mm. Generally, a size on the order ofabout 10 mm is possible.

In a manner which is actually known, where application of the treatmentliquid to be supplied, onto the run-off surfaces, is actually evidentfrom DE 37 33 996 C 2, the supply of liquid to the flat channel can beprovided from above. Also, at the top end of the channel, in a planeperpendicular to the web, run-off surfaces which are inclined downwardtowards the inside of the channel are provided, onto which the treatmentliquid can be applied outside of the footprint of the channel.

In order to maintain foulard-like properties for the impregnationdevice, also with regard to recirculation of the treatment liquidsqueezed off, guide surfaces are provided on both sides of the web,below the pair of squeeze rollers, in a vertical plane perpendicular tothe web, inclined towards the channel, reaching to above the run-offsurfaces, for the treatment liquid squeezed off by the squeezing system.

In an arrangement of the hose section, the flat channel ends, at thebottom, just above the sealing arrangement, and is surrounded, at thebottom end, by a hose section. This hose section is closed in horizontalcross-section and tightly surrounds the channel, which section extendsdown through the sealing arrangement to below the latter, in theflattened state. This arrangement of the hose section is particularlyimportant and forms a problem-free and inexpensively implemented sealbetween the end of the rigid channel and the inflatable hoses, andparticularly ensures a seal with regard to the sides of the web, easilyand without being bound to a certain web width.

A similar hose section is also seen in DE 14 60 265 A 1, but there it isarranged inside the flat channel and attached at its upper edge. Becauseof the height of the dipping or impregnation section, which might belarge for the invention under certain circumstances, this results in thenecessity of arranging a rather long hose section, with thecorresponding costs, where the material really has no sealing functionto fulfill outside of the actual sealing zone. In the invention, on theother hand, the hose section only has to bridge the zone between thebottom end of the flat channel and the sealing arrangement arrangedbelow it.

The characteristic of affixing the hose section on the outside, on theflat channel, is particularly important if a slip film is to be providedat the same time, to facilitate having the web slide through between theinflatable hoses which are opposite one another. It is reasonable thatfor the exemplary embodiment known from DE 14 60 265 A 1, such a slipfilm would be applied only at the top edge of the channel. The slipfilms would then have to extend over the entire height of the flatchannel, or be affixed to the hose section at half the height. Bothsolutions are disadvantageous in terms of design. In the invention,however, slip films which extend over the width of the web are attachedon the outside of the flat sides of the flat channel, but within thehose section, with their top edge, and extend downward through thesealing arrangement to below the latter, are fixed in place there in themovement direction of the web, and rest against both sides of the webunder the pressure force of the sealing arrangement. In this case, theslip films can have an optimum short length, without causing anyproblems in being held in place against the tension of the web.

The hose section and the attachment of the slip films arecharacteristics which can also be applied independent of the questionwhether or not squeeze rollers are applied above the top end of the flatchannel. These characteristics are therefore important in their ownright.

The device may have at least one inflatable, flat, rectangular bag,which is intended to be inserted into the flat channel. The bag extendsover its height with one rectangle side but not over its entire widthwith the other rectangle side, and fills the rectangular region taken upby the bag as a displacement element, in the inflated state. Thisstructure is practical for use and it permits the production of testsamples with a small width, under production-like conditions, withoutusing a large amount of treatment liquid. In this connection, a regionof the channel corresponding to the width of the rectangular bag isfilled in such a way that no treatment liquid can penetrate into thisregion. Only the residual width of the channel remains, for example onone side, through which a narrow strip of a textile material can bepassed and in which only a very small amount of treatment liquid ispresent. The sample strip is treated in the same way as would be thecase later for a wider web. In this way, samples can be produced whichare closer to production conditions than those produced on a laboratorymachine separate from the system.

A rigid strip is affixed at the top edge of the bag, which can be setonto the top end of the flat channel. When a sample is to be produced,the bag is inserted into the channel from above, where the rigid stripforms the contact point at the top end of the channel and holds the bagin the correct position. It is practical if the connection for inflatingthe bag is also provided on the rigid strip.

A practical development is a weighting rod which is provided at thebottom end of the bag and ensures that the bag, which consists offlexible plastic film, can easily be suspended into the flat channelunder the weight of the weighting rod.

When production of samples is finished, the air is let out of the bagand the bag is removed, whereupon the entire width of the flat channelis again available for passing the web through.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a vertical cross-section through an impregnation device,perpendicular to the web.

FIG. 2 shows the region of the sealing arrangement from the bottom ofFIG. 1, on a larger scale.

FIG. 3 shows a horizontal partial cross-section along the line III--IIIin FIG. 2.

FIG. 4 shows a view of a different exemplary embodiment in a viewcorresponding to FIG. 1.

FIG. 5 shows a view according to FIG. 4 from the right.

DETAILED DESCRIPTION OF THE DRAWINGS

The impregnation device indicated as a whole with 100 in FIG. 1 servesto impregnate a web 1, for example a textile web, with a treatmentliquid with a predetermined moisture content. The impregnation device100 comprises an upright, flat channel 10, which can be filled with thetreatment liquid and through which the web 1 passes from the top to thebottom. Towards the bottom, the flat channel is closed off by a sealingarrangement 20, which rests against the web 1 from both sides, and whichprevents the treatment liquid from running down out of the flat channel10.

A squeezing system 20 with two squeeze rollers 32, 33 that work againsteach other is arranged above the flat channel 10; the rollers squeezethe web 1 impregnated in the flat channel 10 to a predetermined moisturecontent, so that a certain amount of treatment liquid remains on the web1, in a uniform distribution.

The web 1 passes from above over a width-stretching roller 2 arrangedbelow the impregnation device 100, is deflected by about 90° there, andreaches a deflection roller 3 in an approximately horizontal position.From the right side in FIG. 1, the web runs vertically upward and viaanother width-stretching roller 4 above the flat channel 10, and thereruns into the roller nip 31 of the squeeze rollers 32 and 33.

The flat channel 10 consists of two rectangular plates of sheet metalwhich are arranged opposite and parallel to one another at a slightdistance, forming the flat sides 5, 5 of the channel 10. The longersides of the rectangular plates are placed in the width direction of theweb. A spacer profile 6, rectangular in cross-section, is arrangedbetween the upright, shorter sides, at the edge in each instance, and onthe outside, shim profiles 7, 7 are opposite these spacer profiles. Thewhole is connected by means of a series of screws 8 and sealed in asuitable manner, so that a closed channel is obtained in horizontalcross-section. At the top and the bottom, the flat channel 10 is open.At the bottom end of the flat channel 10, a support construction isprovided, of which only two I-beams 11, 12 are shown, opposite oneanother at the same height. The beams 11, 12 are located opposite oneanother at a distance, with a cross-brace 11', 12' in each instance. Inthe spacer space, holder pieces 13, 14, 15 are mounted on thecross-braces 11', 12', holding the bottom end of the flat channel 10 andthe sealing arrangement 20 in place. If necessary, the flat channel 10can also be supported at another point, in a manner not shown.

At the top end 10", the plates or pieces of sheet metal forming the flatsides 5, 5 of the flat channel 10 are angled off towards the outside andform run-off surfaces 16 which are inclined inward, via which thetreatment liquid runs down into the top end of the flat channel 10 inthe form of a film or layer, at a slant. Outside of the run-off surfaces16, supply pipes 17 for the treatment liquid are provided; they arehorizontal and extend parallel to the flat sides 5, 5, and are suppliedwith liquid in a suitable manner. The supply pipes 17 are connected witha plurality of consecutive small elbows, in the width direction, whichare bent like canes and reach over the top edge of the run-off surfaces16. The treatment liquid, applied to the run-off surfaces 16 by thesmall elbows 18 at a plurality of rather closely spaced locations, flowsdown over the run-off surfaces 16 and becomes uniform in the process, sothat the flat channel 10 can be kept filled without significantdifferences in level in the width direction of the web 1.

The squeeze rollers 32, 33 are provided above the run-off surfaces 16and the small elbows 18, in the region of the footprint of the flatchannel 10 with its support arrangement. The treatment liquid squeezedoff in the roller nip 31 either flows down along the web 1 or drips off.In order to catch this treatment liquid, guide surfaces 34, 35 areprovided on both sides of the web 1, which catch the treatment liquidoccurring below and to the side of the squeeze rollers 32, 33, and passit to the run-off surfaces 16, where it is brought back into the flatchannel 10.

In FIG. 2, the region of the sealing arrangement 20 from FIG. 1 is shownon a larger scale. The sealing arrangement 20 comprises two inflatablehoses 25 which are opposite one another on both sides of the web 1, atthe same height, and which have T-shaped ribs on the back, continuous inthe lengthwise direction, which engage into corresponding undercutrecesses 27 of the holder pieces 13 and 14, respectively. In thecompletely inflated state, the hoses 25 rest against one another withpressure. In the pressure-free or evacuated state, they are flat, asindicated with broken lines at 25' in each instance. The arrangement ofthe hoses 25, 25 is made in such a way that in the inflated state, theyhold the web 1 in the center of the flat channel 10.

The sealing arrangement 20 is arranged just below the bottom end 10' ofthe flat channel 10. In the region of the bottom edge, the flat channel10 is surrounded on its outside by a short hose section 40 made ofplastic film which tightly encloses the flat channel 10. In other words,the hose section 40 is dimensioned, in its horizontal cross-section, insuch a way that it precisely fits around the flat channel 10 and can besealed relative to it, if necessary using sealing agents. The hosesection is clamped in place between the outside of the flat sides 5 andholder brackets 29, which are supported on the holder pieces 15 or 13and 14, respectively. The hose section 40 hangs down over the bottom end10' of the flat channel 10 and passes between the hoses 25, 25, and thenextends slightly further to its bottom edge 40'.

Between the holder brackets 29 and the outside of the flat sides 5, aslip film 50 is also clamped in place with its top edge, on each side ofthe web 1, on the inside of the hose section 40. The slip films 50extend within the hose section 40 through the gap between the hoses 25,25, and are attached on resilient brackets 42 at their bottom end, at41, which hold the slip films 50 against the friction entrainment forcesof the web 1, which runs from the bottom to the top.

The slip films 50, 50 rest directly on the web 1 and consist of adurable material which promotes slip, e.g. polytetrafluoroethylene orcorrosion-resistant steel. Because of their attachment at 41, they holdthe hose section 40 and therefore remain free of forces which act in thedirection of movement of the web 1. The hose section 40 therefore has apurely sealing function, without any claims to mechanical strength orparticularly good slip-promoting properties. In particular, the problemof sealing the spacer space between the bottom end 10' of the flatchannel 10 and the sealing arrangement 20 is solved in a simple manner.

FIG. 3 shows a horizontal cross-section at the height of the hoses 25,25 in the edge region of the web 1. The thickness relationships areshown in exaggerated manner. Because of the elasticity of the hoses 25,25, the slip films 50, 50 and the edges of the hose section 40 outsidethe edge 1' of the web are compressed and sealed by means of theinterior pressure of the hoses 25, 25, so that an exact adaptation ofthe width of the web to the width of the slip films 50, 50 and the hosesection 40 is not important.

In FIG. 1, the flat channel 10 is interrupted at the height of thelocation 19. This is to indicate that the height of the channel 10 andtherefore of the impregnation section can be different, if necessary. Inpractice, a height of about 400-500 mm is possible.

FIGS. 4 and 5 show a supplemental device which allows efficient andproduction-like manufacturing of sample strips 70 in the impregnationdevice 100. The supplemental device consists of an inflatable bag 60made of plastic film, which is sealed except for a connection 66. Thebag has a rectangular outline and is shown with heavy broken lines inFIG. 5. The bag 60 has a top edge 61, a bottom edge 62, and verticaledges 63, 64, the distance between which, i.e. the width of the bag 60,is less than the width of the flat channel 10, so that room remains fora narrow sample strip 70, on the right side in the exemplary embodiment.At the top edge 61 of the bag 60, a rigid strip 65 which covers theentire width is attached, closing the bag off towards the top andstabilizing it, and resting against the top edge 10" of the flat channel10. A weighting rod 68 lies in the bottom of the bag 60.

If samples are to be produced, the bag 60 is suspended into the flatchannel 10, which can easily be done because of the weighting rod 68which pulls the bottom edge 62 of the bag 60 down. The rail 65 thenrests against the top edge 10" of the flat channel 10. The bag is pumpedup with air through the connection 66 on the rail 65, and then fills theleft region of the flat channel 10 like a displacement element, inaccordance with its width, between the vertical sides 63, 64, i.e. thesides which run parallel to the delimitations of the channel 10, so thatno treatment liquid can penetrate there any more, and only the narrowregion of the sample strip 70, which is not reached by the bag 60,remains free. Therefore only a very small amount of treatment liquid isnecessary for producing the samples. Accordingly, production of thesamples takes place in the same manner as subsequent production, so thatthe samples exactly reproduce the result of the treatment. Aftercompletion of production of the sample 70, the air is let out of the bag60 and the bag is lifted out upwards, so that the entire working widthis available again.

We claim:
 1. A device for impregnating a web laterally guided in thewidth direction with a treatment liquid, the device comprising:a tankthrough which the web is passed for impregnation with the treatmentliquid as it traverses the tank in an upwardly direction, said tankhaving an upright flat channel that serves to contain the treatmentliquid it is passed to the web, the upright flat channel having flatfacing sides which are tightly opposed and configured to extendgenerally parallel to the web, wherein the upright flat channel has anupper end and a lower end; a resilient sealing arrangement which isarranged substantially below the lower end of the upright flat channeland which presses on the web from both sides and wherein the uprightflat channel can be kept charged with the treatment liquid to a desiredlevel; a means for guiding the web upwardly through the tank; and a pairof squeeze rollers for impinging on the web, said squeeze rollers beinglocated above the tank so that they impinge upon the web after it hasleft the upright flat channel.
 2. The device according to claim 1,wherein the resilient sealing arrangement comprises a flexible wall thatextends crosswise across the web, and wherein said wall can be inflatedby a fluid pressure medium so that it is pressed tightly against oneside of the web and forms a seal therewith by pressing the web against acounter-surface on the other side of the web.
 3. The device according toclaim 2, further comprising an inflatable, flexible wall on each side ofthe web.
 4. The device according to claim 3, wherein the flexible wallsare formed by inflatable hoses which lie opposite one another.
 5. Thedevice according to claim 4, wherein the walls of the upright flatchannel are made of a rigid material.
 6. The device according to claim1, wherein the walls of the upright flat channel are made of a rigidmaterial.
 7. The device according to claim 6, wherein the flat sides ofthe upright flat channel include two rectangular plates which arearranged opposite and parallel to one another at a distance, which aretightly connected with one another on upright edges by means of edgeridges made of a rectangular profile, arranged between them.
 8. Thedevice according to claim 7, wherein the distance between the flat sidesof the upright flat channel is about 6 to 15 mm.
 9. The device accordingto claim 6, wherein the distance between the flat sides of the uprightflat channel is about 6 to 15 mm.
 10. The device according to claim 9,wherein the upper end of the upright flat channel is open so that it canbe supplied with the treatment liquid from above.
 11. The deviceaccording to claim 1, wherein the upper end of the upright flat channelis open so that it can be supplied with the treatment liquid from above.12. The device according to claim 11, further comprising run-offsurfaces at the upper end of the upright flat channel, in a planeextending laterally from the channel, the run-off surfaces beinginclined downward towards the inside of the channel, wherein thetreatment liquid can be applied to the run-off surfaces from a locationthat is exterior to the channel.
 13. The device according to claim 12,further comprising guide surfaces located on either side of the web,extending from below the pair of squeeze rollers downwardly to aposition above the run-off surfaces, the guide surfaces directing flowof the treatment liquid from the squeeze rollers to the run-offsurfaces.
 14. The device according to claim 1, further comprisingrun-off surfaces at the upper end of the upright flat channel, in aplane extending laterally from the channel, the run-off surfaces beinginclined downward towards the inside of the upright flat channel,wherein the treatment liquid can be applied to the run-off surfaces froma location that is exterior to the upright flat channel.
 15. The deviceaccording to claim 14, further comprising guide surfaces located oneither side of the web, extending from below the pair of squeeze rollersdownwardly to a position above the run-off surfaces, the guide surfacesdirecting flow of the treatment liquid from the squeeze rollers to therun-off surfaces.
 16. The device, according to claim 14, wherein thelower end of the upright flat channel terminates just above the sealingarrangement, and wherein the extending downwardly from the lower end ofthe upright flat channel is a section of hose which is closed inhorizontal cross-section and which tightly surrounds the upright flatchannel, wherein the hose section extends down through the sealingarrangement to below the sealing arrangement in a flattened state.
 17. Adevice for impregnating a web laterally guided in the width directionwith a treatment liquid, the device comprising:a tank through which theweb is passed for impregnation with the treatment liquid as it traversesthe tank in an upwardly direction, said tank having an upright flatchannel that serves to contain the treatment liquid it is passed to theweb, the upright flat channel having flat facing sides which are tightlyopposed and configured to extend generally parallel to the web, whereinthe upright flat channel has an upper end and a lower end, the lower endbeing limited by a resilient sealing arrangement that can be brought tobear on the web from both sides and wherein the upright flat channel canbe kept charged with the treatment liquid to a desired level; and a pairof squeeze rollers for impinging on the web, said squeeze rollers beinglocated above the tank so that they impinge upon the web, after it hasleft the upright flat channel, wherein the lower end of the upright flatchannel terminates just above the sealing arrangement, and wherein theextending downwardly from the lower end of the upright flat channel is asection of hose which is closed in horizontal cross-section and whichtightly surrounds the upright flat channel, wherein the hose sectionextends down through the sealing arrangement to below the sealingarrangement in a flattened state.
 18. The device according to claim 17,further comprising slip films which extend over the width of the web andare attached on the outside of the sides of the upright flat channel,but within the hose section, at their top edge, and extend downwardthrough the sealing arrangement to below the sealing arrangement,wherein the slip films are fixed in place in movement direction of theweb and rest against both sides of the web under pressure force of thesealing arrangement.
 19. The device according to claim 18, furthercomprising at least one inflatable, flat, rectangular bag, wherein therectangular bag is configured to be inserted into the upright flatchannel such that it then extends, above the upright flat channel butextends across only a portion of the lateral width of the upright flatchannel, said rectangular bag extending across the width defined by thefacing sides of the upright flat channel when the rectangular bag, isinflated.
 20. A device for impregnating a web laterally guided in thewidth direction with a treatment liquid, the device comprising:a tankthrough which the web is passed for impregnation with the treatmentliquid as it traverses the tank in an upwardly direction, said tankhaving an upright flat channel that serves to contain the treatmentliquid it is passed to the web, the upright flat channel having flatfacing sides which are tightly opposed and configured to extendgenerally parallel to the web, wherein the upright flat channel has anupper end and a lower end, the lower end being limited by a resilientsealing arrangement that can be brought to bear on the web from bothsides and wherein the upright flat channel can be kept charged with thetreatment liquid to a desired level; a pair of squeeze rollers forimpinging on the web, said squeeze rollers being located above the tankso that they impinge upon the web after it has left the upright flatchannel; and at least one inflatable, flat, rectangular bag, wherein therectangular bag is configured to be inserted into the upright flatchannel such that it then extends above the upright flat channel butextends across only a portion of the lateral width of the upright flatchannel, said rectangular bag extending across the width defined by thefacing sides of the upright flat channel when the bag is inflated. 21.The device according to claim 20, further comprising a rigid stripaffixed at a top edge of the bag, wherein the rigid strip can be setonto the top end of the upright flat channel.
 22. The device accordingto claim 21, further comprising a connection on the rigid strip forinflating the bag.
 23. The device according to claim 22, furthercomprising a weighting rod at the bottom edge of the bag.
 24. The deviceaccording to claim 20, further comprising a weighting rod at the bottomedge of the bag.